The present invention relates generally to fuel dispensers and, more particularly, to fuel dispensers for precisely delivering and controlling the rate of fuel flow to a vehicle based upon information received from the vehicle during a fueling operation.
Federal regulations limit vehicle fueling to ten gallons per minute (GPM) in order to achieve legislated limits on the amount of spillage from vehicle fueling operations. See 58 Federal Register 16019. Conventional gasoline dispensers are restricted to a maximum delivery rate of 10 GPM in an effort to reduce fuel spit-back and spillage and the resultant exposure of fuel to customers and the environment. The current technology (i.e. prior to this invention) for restricting fuel delivery rate on gasoline dispensers is to install restrictive orifices at accessible points in the delivery system and/or various hose and nozzle configurations (known as hanging hardware,) accordingly.
The state of the art does not provide a way to optimize fuel delivery while abiding by the government regulations. Current fuel dispensers cannot maximize delivery rates and/or maintain an average fuel delivery rate of 10 GPM during a substantial portion of or throughout the fueling operation while minimizing spillage. Dispensers are limited because information relating to fuel tank ullage and maximum allowable delivery rates is unavailable. Additionally, current dispensers are unable to precisely control fuel delivery throughout the fueling operation. The dispenser cannot predict maximum vehicle fueling rates or the end of the fueling operation in order to precisely control fuel delivery during the fueling operation in order to maximize fueling rates while staying within regulated flow rate averages and minimizing spillage. Different vehicles have different fueling capabilities. Current dispensers are unable to recognize these differences to adjust their performance to optimize fueling. Many vehicles may be fueled at rates significantly higher than 10 GPM, without threat of spillage during most of the fueling operation. If a dispenser could determine the vehicle's fueling capability, fueling could occur at varying rates throughout the fueling operation to obtain an overall average of 10 GPM, without threat of spillage during most of the fueling operation. Thus, the fueling time and spillage could be minimized, while abiding by regulatory mandates.
The accuracy of restricted orifices and hanging hardware inherently suffers from fluctuations in system feed pressure. System feed pressure is affected by a number of variables including the number of active fueling positions, clogged fuel filters, kinked hoses and other deteriorating components along a fuel delivery path. The requisite restriction is dependent upon site specifics, such as, but not limited to, pumping device capacity, pipe diameter, pipe length, head height, hose diameter, hose length and nozzle type. These factors prevent effective factory presetting of desired fuel delivery rates. Moreover, orifices and hardware are subject to tampering, removal or substitution in an effort to defeat flow restrictions. When fuel pumps incorporating the current technology are checked for compliance with the regulations, the testing authority will check the highest flow delivery hose, typically the hose closest to the main turbine pump, with all other hoses inactive. Once adjustments are made to limit the high-flow hose to 10 GPM, the lower flow hoses will inherently deliver less than 10 GPM. The situation is exacerbated when multiple pumps are active. Under these situations, even the highest flow hose will often deliver significantly less than 10 GPM.
Conventional individual fuel dispensers are unable to optimize and control fueling in multi-dispenser systems. Additionally, the current technology cannot provide precise regulation of fuel delivery under varying dynamic changes affecting the fuel delivery rate by site, dispenser, user and other variables. For example, substantial changes in pressure within the fuel delivery system occur when other dispensers within the system turn on or off, or adjust fueling rates. Currently, these changes in pressure prevent precise fueling regulation and optimization. Furthermore, current fuel dispensers are unable to adequately control delivery rate overshoot and undershoot or provide sufficient system response times. Without such control, precisely controlling a fueling operation is virtually impossible.
Current dispensers are unable to precisely control the ramping up of the delivery rate to prevent an initial surge at the onset of fueling or the ramping down of the flow rate to quickly and efficiently reach pre-set sale values or quantities. Providing a fuel dispenser capable of precisely controlling the entire fueling operation based on fueling parameters received from a vehicle, particular to that vehicle, would enable a very smooth, quick and efficient fueling operation.
Although it is well-known in the art at this time to provide communications between a fuel delivery system and a vehicle, none of the existing dispensers are capable of precisely controlling a fueling operation to maximize fueling efficiency based on information received from the vehicle to be fueled. Many systems are available which are capable of recognizing a vehicle automatically and providing communications to and from the vehicle from a fuel dispenser to keep track of customer billing or automobile diagnostics. U.S. Pat. No. 5,072,380 to Randelman et al. and U.S. Pat. No. 5,557,268 to Hughes et al. are exemplary of these systems. U.S. Pat. Nos. 5,359,522 and 5,204,819 to Ryan disclose the use of two-way RF communication systems between a vehicle computer and a fuel dispenser computer. The communication systems provide automatic activation of the fuel delivery transaction, identification of the fluid container for security and billing purposes, automatic payment without use of an identification card and memorializing fluid delivery transactions. Also disclosed is a passive communication device which uses part of the energy transmitted from the fuel dispenser for power.
U.S. Pat. No. 5,383,500 to Dwars et al. discloses a system controlling the automatic refueling of vehicles in a manner allowing a customer to control the refueling procedure without exiting the vehicle. The communications system has the capability to start, monitor and finish the refueling procedure by transmitting and receiving data signals concerning the refueling procedure, such as signals which start the refueling procedure and interrupt that procedure. Communication between the vehicle and dispenser is possible through infrared, electromagnetic or acoustic wave transmission.
U.S. Pat. No. 5,343,906 to Tibbels, III discloses a communication system linking a computer of a vehicle to a computer of a fuel dispenser via an electrical or fiber optic connection. The system validates emissions by monitoring various emissions and diagnostic aspects of the vehicle, storing the information and communicating the information to a fuel dispenser. The system is capable of maintaining a record of the vehicle's fueling and emissions history.
U.S. Pat. No. 4,934,419 to LaMont et al. discloses a fuel management system where an on-board computer communicates with a fuel dispenser using fiber optics. The disclosure primarily focuses on the management of information used in the operation of fleet vehicles. U.S. Pat. No. 5,156,198 to Hall discloses the use of a common core transformer for communications between a vehicle's on-board computer and a fuel dispenser computer. The dispenser identifies the vehicle, the amount of fuel supplied to the vehicle, the vehicle mileage since the last fueling, the date of such fueling, and the time of actual use of the vehicle.
The above references are indicative of the state-of-the-art relating to communications between a vehicle and a fuel dispenser. Various communication methods are used in such communications and a variety of information ranging from fueling data and vehicle identification to a emission control and vehicle monitoring are disclosed. However, none of the references discuss or suggest controlling delivery rate to optimize fueling efficiency based on information received from the vehicle to be fueled. The applicants' invention provides this capability.
U.S. patent application Ser. No. 08/650,917, filed May 17, 1996 to Payne et al. discloses a precision fuel dispenser capable of controlling fuel delivery throughout the fueling operation. U.S. patent application Ser. No. 08/759,733, filed Dec. 6, 1996 to Hartsell, Jr. et al. discloses an intelligent fueling system capable of communicating with vehicles and determining their approximate location with respect to a fueling position. Both of these applications are owned by Gilbarco, Inc. of Greensboro, N.C. (the owner of the present application), and their disclosures are incorporated herein by reference. These applications provide additional disclosure of aspects relating to the current invention.
A precisely controlled fueling operation provides greater environmental protection capability by minimizing fuel spillage and spit-back. By reducing the initial surge at the onset of fueling and ramping down the flow rate towards the end of fueling, the amount of fuel spilled is greatly reduced. Furthermore, precisely controlling the fuel delivery allows precise flow rate control dependent upon a number of predetermined cut-offs during a predetermined period of time. Rapid, successive cut-offs indicate splash-back or excessive turbulence in the nozzle's fill neck, a condition likely to lead to fuel spills. Fuel dispensers are currently unable to control the fueling operation to effectively react to scenarios leading to fuel spills. If the dispenser could predict or determine the end of the fueling operation by the amount of fuel required to fill the vehicle's tank, the end of the fueling operation could be controlled accordingly without affecting the maximum fueling rates during the majority of the fueling operation. The applicants' invention provides such control to both minimize fuel spills and optimize fueling.
A further disadvantage of current fuel dispensers is the inability to automatically compensate for deteriorating components which nominally reduce flow. Components which often reduce flow include clogged fuel filters and kinked hoses. The applicants' invention allows fueling optimization even when the system components are not optimum. For example, as the fuel filter fills with debris, the flow control signal to the system fuel pump is increased in an amount to precisely compensate for any flow rate loss.
Thus, there remains a need for a new and improved fuel dispenser capable of optimizing fuel flow rate per regulatory agency mandate while maximizing site throughput under varying dynamic conditions based upon information received from the vehicle being fueled. A need remains for a fuel dispenser capable of receiving fueling parameters, such as tank size, ullage, and maximum fueling rate as a function of ullage from a vehicle in order to control or adjust the delivery rate of fuel to the maximum that the vehicle being fueled can accept without causing excessive spillage. A need not only exists for a fuel dispenser capable of instantaneously adjusting the fuel delivery rate to maximize fueling, but also to control the delivery rate throughout the fueling operation to optimize fueling efficiency within the confines of regulatory mandates and dispenser or vehicle limitations. A further need exists for a fuel dispenser capable of determining a fueling operation function which determines the various fueling rates throughout the fueling operation based on fueling parameters received from the vehicle to be fueled. A need exists for a fuel dispenser capable of delivering fuel at precise flow rates independent of site variations and capable of being manufactured in a manner requiring no field modifications or calibrations.